如何在 lua love 引擎中检测与折线的碰撞？答案

【问题标题】：How do I detect a collision with a poly line in the lua love engine?如何在 lua love 引擎中检测与折线的碰撞？
【发布时间】：2013-10-04 07:34:48
【问题描述】：

我正在使用 lua love 引擎制作一个简单的游戏。但是，我在碰撞时遇到了一点麻烦。

我在一组点（代表岩石地面）和一个我需要与之碰撞的盒子之间有一条折线，但我想不出一个简单的实现方式。

love.graphics.line( 0,60, 100,70, 150,300, 200,230, 250,230, 300,280, 350,220, 400,220, 420,150, 440,140, 480,340 )

如果有人可以帮助提供代码 sn-ps 或建议，将不胜感激。

【问题讨论】：

标签： lua collision-detection

【解决方案1】：

您需要创建一个更抽象的地面表示，您可以从中生成图形的线条和物理的主体。

例如：

--ground represented as a set of points
local ground = {0,60, 100,70, 150,300, 200,230, 250,230, 300,280, 350,220, 400,220, 420,150, 440,140, 480,340}

这可能不是最好的表示，但我会继续我的例子。

您现在有了地面的表示，现在您可以转换物理可以理解的东西（进行碰撞）和图形显示可以理解的东西（绘制地面）。所以你声明了两个函数：

--converts a table representing the ground into something that
--can be understood by your physics.
--If you are using love.physics then this would create 
--a Body with a set PolygonShapes attached to it.
local function createGroundBody(ground)
    --you may need to pass some additional arguments,
    --such as the World in which you want to create the ground.
end

--converts a table representing the ground into something
--that you are able to draw.
local function createGroundGraphic(ground)
    --ground is already represented in a way that love.graphics.line can handle
    --so just pass it through.
    return ground
end

现在，把它们放在一起：

local groundGraphic = nil
local groundPhysics = nil
love.load()
    groundGraphic = createGroundGraphic(ground)
    physics = makePhysicsWorld()
    groundPhysics = createGroundBody(ground)

end

love.draw()
    --Draws groundGraphic, could be implemented as
    --love.graphics.line(groundGraphic)
    --for example.
    draw(groundGraphic)
    --you also need do draw the box and everything else here.
end

love.update(dt)
    --where `box` is the box you have to collide with the ground.
    runPhysics(dt, groundPhysics, box)
    --now you need to update the representation of your box graphic
    --to match up with the new position of the box.
    --This could be done implicitly by using the representation for physics
    --when doing the drawing of the box.
end

如果不确切知道您想如何实现物理和绘图，很难提供比这更详细的信息。我希望您以此为例来说明如何构建此代码。我提供的代码只是一个非常近似的结构，因此它不会接近实际工作。有什么不清楚的地方请教！

【讨论】：